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Parasitic infections: causes, symptoms.

Parasitic infections represent a variety of symptoms and diseases caused by the invasion of the human body by eggs or adult parasites.The first signs of illness often only become apparent after several days, and in some cases only after several months or even years.This is due to the life cycle of the parasites and their main functions: good camouflage and maintaining their own life by absorbing nutrients from the host's body.

Types of parasites and their characteristics

Parasitic infections are divided into three groups depending on certain characteristics of their manifestation:

  1. Ectoparasites.
    The main place is the surface of the human body.These include lice, fleas, ticks and bed bugs.They feed predominantly on human blood, although in some cases, such as mites that cause demodicosis, the main food is the secretion of the sebaceous glands or dead epithelial (skin) cells.EctoparsitesThe first signs of a parasite infection are quite easy to recognize as they cause itching and burning in their habitats.Some ectoparasites are carriers of serious diseases: typhus, anthrax, encephalitis and trypanosomiasis.They cause enormous damage to health and even death.
  2. Endoparasites (protozoa).
    Mainly affects internal organs.They are unicellular, hence the name protozoa.However, they can lead to serious illnesses.The main diseases in this group are parasitic blood infections caused by toxoplasma and intestinal infections caused by amoeba or giardia.
  3. Helminths.
    They are the causative agents of the most common forms of parasitic infections.In the human body, their development cycles take place mainly in the intestines and tissues, where the manifestation of disease symptoms begins.

Roundworms (nematodes)

These are parasites whose bodies are round in cross section.Sexual characteristics are easy to distinguish.Females are usually larger than males.But representatives of this class also have hermaphrodites.All nematodes go through developmental stages: egg, larva and adult.This class includes:

  1. Pinworm.The disease is caused by enterobiasis.Children of preschool and primary school age are particularly affected.
  2. Whipworm.Causes the disease trichuriasis.Has a pronounced body shape.2/3 of the body length have a thin diameter reminiscent of human hair or thread.The other end of the body is larger in diameter and contains the intestines.
  3. Ascaris.The disease is caused by ascariasis.Adults reach a size of 25 cm (males) and 40 cm (females).After the larva enters the human body, it passes through the stomach and enters the small intestine.From there it passes through the pores with the blood flow to the liver, then to the heart and then to the lungs, where it develops within 7-10 days.Then the larvae begin to ascend to the larynx.As soon as they reach the oral cavity, they are swallowed again.Once in the small intestine, the larvae cannot get back into the bloodstream through the pores due to their size.There they grow into adults within 2-3 months.After that, reproduction begins and the cycle repeats itself.The female can lay more than 200,000 eggs per day.
Roundworms

Tapeworms (cestodes)

These are parasites whose bodies are shaped like a band.A distinctive feature of this class is the lack of a digestive system.This includes:

  1. Echinococci.The disease is caused by echinococcosis.This parasite is small (2–9 mm) and consists of multiple segments and suckers.The uterus of a sexually mature individual contains a large number of eggs in which there are larvae.The main sites of localization of echinococci are the liver and lungs.There it causes a chronic disease called udder cyst.
  2. Bull tapeworm.Causes the disease teniarinchiasis.In the larval stage it has an intermediate host - cattle.Once in the human body, it develops into the band stage in the small intestine.The body of an adult parasite consists of up to 1000 segments and can reach a length of 4 to 10 meters.
  3. Pork tapeworm.Causes the disease taeniasis.Externally it closely resembles the bull tapeworm.There are also intermediate hosts: pigs, dogs, camels, hares and rabbits.In humans it is a parasite in the intestines.The size of an adult individual does not exceed 4 meters in length.
  4. The tapeworm is wide.The disease is caused by diphyllobothriasis.Lives in freshwater waters.Crustaceans and fish serve as intermediate hosts.In the human body, it parasitizes in the small intestine.An adult can reach several meters in length.

Flatworms (leeches)

During their life cycle, these parasites can change several intermediate hosts.In humans, they can be parasitized in any organ.This group includes:

  1. schistosomes.The disease is caused by schistosomiasis.They can enter the human body through contact with contaminated fresh water.The parasite penetrates the skin and enters the circulatory system, where it begins to actively multiply.Females can produce 300 to 3000 eggs per day.In addition, the eggs are distributed throughout the body through blood flow and continue to develop in every organ.Their body length is no more than 0.1–0.2 cm.
  2. Liver fluke.The disease is caused by opisthorchiasis.The length of an adult varies between 3 and 5 cm.When it enters the human body, it parasitizes in the bile ducts, gallbladder, liver and pancreas.Fixation in these organs occurs via suction cups attached to the body.
Liver fluke

Ways of invasion of parasites into the human body

  1. The nutritional route of infection is considered the most common.A person becomes infected with the parasite by eating poorly washed vegetables and fruits.Meat that has not been adequately heat-treated is particularly dangerous.Also, a person becomes infected with a parasitic infection if the rules of personal hygiene are not followed.For example, don't wash your hands before eating.
  2. Transplacental route.The parasitic infection is transmitted from a pregnant woman to the child through the placenta.These include, for example, diseases such as toxoplasmosis, malaria or hookworms.
  3. Percutaneous route.The parasite enters the human body through the skin.These are mainly schistosomes and hookworms.
  4. Contact path.The parasite is transmitted through dirty hands, contaminated personal items and underwear.Lice, scabies and pinworms are most commonly transmitted this way.
  5. transmission route.Infection occurs after the bite of insects that transmit parasites.For example malaria.

Symptoms

Many parasitic diseases have no symptoms in the early stages.This is due to the developmental stages of the pathogen.Each type of parasite manifests itself differently as it grows.Common general symptoms of a parasite infection include:

  1. Itching.
  2. Redness of the skin like urticaria.
  3. Diarrhea.
  4. Constipation.
  5. Flatulence.
  6. Nausea, vomiting.
  7. Cramps and pain in the gastrointestinal tract.
  8. Lose weight without diet or increased physical activity.
  9. Febrile condition.
  10. High body temperature (38-40°C) for a long period of time.
  11. Prolonged bouts of dry cough.
  12. Enlarged lymph nodes.
  13. Painful sensations in the muscles.
  14. Psycho-emotional disorders.

diagnosis

diagnosis

If you suspect the presence of parasitic diseases, you will need to undergo a series of tests.Diagnosis of parasitic infections allows us to determine the presence or absence of a parasite, as well as its type and location in the body.The data obtained helps the doctor make the correct diagnosis and prescribe the correct treatment.

Diagnostic methods include:

  1. Stool examination.Allows you to determine the presence of most types of parasites living in the intestines.Their eggs, larvae and body parts are excreted in the feces.There are two types of analysis:
    1. A stool sample is examined for helminth eggs and larvae.The analysis is delivered to the laboratory, where the doctor takes swabs and examines them under the microscope.This method is commonly used but is not accurate enough.To make a definitive diagnosis, the patient must undergo this test up to three times at short intervals.This is due to the parasite life cycle and egg laying detected using this research method.
    2. Scratching (washing) from the folds of the anus.This test is used to detect only one type of helminth - pinworms.Parasitic infections are more common in children than in adults.For this reason, this analysis is mainly carried out for children.The laboratory technician moistens a cotton or glass eye swab with water or glycerin and rinses it from the perianal folds.The resulting material is then applied to a microscope slide and examined under a microscope.This analysis is also carried out using a different method: a laboratory assistant sticks a piece of adhesive tape to the anal canal, presses it on and pulls it off.The adhesive tape is then stuck onto a microscope slide and also viewed under a microscope.The parasite is diagnosed quite accurately.Using these methods, the laboratory assistant is able to examine not only worm eggs, but also sometimes adult individuals.
  2. Examination of cerebrospinal fluid, sputum, duodenal contents (bile), urine.Prescribed based on the results of a patient survey to determine the presence of the parasite and determine its location.These biological fluids are analyzed using microscopy and macroscopy.First, the resulting sample is examined for the presence of adult individuals, and then microscopy is carried out to detect eggs and larvae of parasites.
  3. Blood sample.Modern methods of examining blood for parasitic infections make it possible to determine the presence and type of pathogen with high accuracy.Three types of such diagnostics are used:
    1. Serological reactions.Allows you to determine the presence of parasite antibodies in the patient's blood serum.This method is considered highly specific, but is inferior to PCR diagnostics.
    2. PCR diagnostics.This method is based on identifying the DNA of parasites in each biological fluid sampled for analysis.
    3. Genetic research.The genome of the parasite is detected in a patient's blood sample.This method is used significantly less often than all others, but has high accuracy.
  4. Examination of biopsy material and lymph nodes.For this analysis, the doctor removes a small section of an organ, tissue or an entire lymph node and sends it for histological examination.In this way the presence or absence of parasites is diagnosed.

Recommendations for exam preparation

Before taking tests for parasitic infections, you need to prepare properly.If the recommendations are followed, the accuracy of the diagnosis increases, since the material does not contain interfering factors that reduce the effectiveness of research methods.

Preparing for a stool test:

  1. Antibiotics, anti-inflammatory medications, and antacids should be discontinued.Taking medications and other medicines containing bismuth and iron is also unacceptable.
  2. If an X-ray examination with barium or a colonoscopy was carried out, during which an enema was performed to cleanse the intestines, a stool examination can be carried out only after 2-3 days.
  3. It is not recommended to donate stool when menstrual bleeding begins or hemorrhoids worsen.

Preparing for a blood test:

  1. It is necessary to stop taking pharmacological drugs that affect blood counts.
  2. Three days before the test, you should eat a light diet, avoid eating fatty foods and avoid alcohol.
  3. A blood test for parasitic infections is done on an empty stomach.It is allowed to drink a small amount of clean drinking water.

For other tests, no special preparation is usually required.All you need to do is follow the doctor's recommendations.

Treatment

Unfortunately, symptoms of a parasitic infection cannot always be recognized in the early stages of the disease.In such cases, treatment starts late.It is important to understand: the longer the parasite stays in the body, the more difficult it will be to get rid of it.

The treatment of infectious and parasitic infections is divided into two areas:

  1. Symptomatic treatment.The aim is to eliminate the clinical manifestations of the disease.These include lowering body temperature, eliminating redness and itching, and normalizing the functioning of the gastrointestinal tract.
  2. The etiological treatment of parasitic infections is aimed at eliminating the causative agent of the disease.

In some cases, surgery may be necessary.It is applicable in alveococcosis, echinococcosis and some types of trematode infections.

If the body is dehydrated, saline solutions are prescribed.

Only a doctor can prescribe treatment for parasitic infections based on laboratory tests and patient surveys.

prevention

It is very important to pay attention to the prevention of parasitic infections.In most cases, this prevents pathogens from entering the body.

prevention

Preventive measures include:

  1. Compliance with the rules of personal hygiene: you must wash your hands before eating, after using the toilet and after coming home from the street.
  2. Vegetables and fruits should be washed well.
  3. Adequate heat treatment of meat, fish and seafood is essential.
  4. Tap water should not be used as drinking water as it may not always be free of parasites.Using home filters as additional cleaning will not help.It is best to drink boiled water or bottled water.
  5. When pets live at home, they need to be dewormed every six months.You should also limit contact with your pet if it shows signs of a parasitic disease and contact a veterinary clinic.
  6. You should iron underwear (especially children's underwear) after washing.
  7. After visiting exotic countries, working with land, as well as employees of children's institutions, it is recommended to be examined once a year for the presence of parasitic infections and, if necessary, to carry out drug prophylaxis.